INTERAMERICAN METROLOGY SYSTEM (SIM 2

Transcription

1 INTERAMERICAN METROLOGY SYSTEM (SIM 2.2) INTERCOMPARISON OF WAVELENGTH SCALE AND PHOTOMETRIC SCALE OF SPECTROPHOTOMETRY LABORATORIES Arquímedes Ruiz 1, Joanne Zwinkels 2, Iakyra Bougleux 3, Sally Bruce, Edward Early, and P. Yvonne Barnes 4 1 Optical and Radiometric Division, National Metrology Center, Querétaro, C.P México 2 Photometry and Radiometry, National Research Council, Ottawa, Ontario K1A 0R6 3 Optical Metrology Division, Brazilian Institute of Metrology, Rio de Janeiro, Brazil 4 Optical Technology Division, National Institute of standards and Technology, Gaithersburg, MD 20899, USA Revised: May 18, 2000 Abstract An intercomparison of the photometric scales and wavelength scales of four commercial spectrophotometers located at;, Querétaro (México);, Ottawa (Canada),, Rio de Janeiro (Brasil) and, Gaithersburg, MD (USA), was realized in NORAMET and SIM was accomplished using a holmium oxide filters with wavelength range from approximately 240 nm to 640 nm, Didymium glass and two set of neutral glass filters with nominal transmittances of 1%, 3%, 10%, 30%, 50%, and 90 % over the wavelength range from 220 nm to 650 nm. This comparison is very important for,,, and because it allows to give traceability and confidence in measurements results for all countries, the quality of the calibration services as well as estimating the errors, verify the results obtained by different techniques of the systems and instruments, and allows us to verify the difference among the results from the spectrophotometers of the laboratories than the total average and uncertainty. P. Yvonne Barnes is formerly of 1/26

2 CONTENTS 1 INTRODUCTION MATERIALS (STANDARDS IDENTIFICATION) DESCRIPTION OF THE INSTRUMENTATION GENERAL CHARACTERISTICS OF INSTRUMENTS UNCERTAINTY RESULTS DISCUSSION AND CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES /26

3 1 Introduction This document presents the intercomparison results of the photometric scale and the wavelength scale calibration of the spectrophotometers, these values are based on the use of Standards Reference Materials 1, illustrating the performance of the wavelength and photometric standards and how well four national standardizing laboratories agree using high quality samples. The Standards consists of a solution of holmium oxide in perchloric acid, a holmium oxide glass filter, a Didymium glass filter, and neutral density filters. This intercomparison of the spectrophotometry laboratories was made among the National Metrology Center of Mexico (), National Research Council of Canada (), Brazilian Institute of Metrology () and National Institute of Standard and Technology of USA (). Measurement systems compared are double beam spectrophotometers, mentioning: Varian Cary 5E 2 is principal instrument used by and in support the requests for photometric and wavelength scale measurements, while at and was used the Perkin-Elmer Lambda- 19, the instruments are used as a primary standard transfer instrument. The spectral range of the VARIAN/CARY 5E spectrophotometers is from 175 nm to 3300 nm, and the Perkin-Elmer Lambda- 19 spectrophotometers is from 175 nm to 3200 nm. One particular characteristic of these measurements, in these types of instrument, is the spectral bandwidth parameter, which is user selectable in the ultraviolet to visible spectral range. Additionally, these instruments have been characterized using absolute methods; on the wavelength scale: through physical constants such as spectral atomic emission, and to the photometric scale: through double aperture method or reference beam attenuator. The first measurements and results obtained in spectrophotometry laboratory of,, and were done to study the so called parameters of influence with direct effects that can cause variation in the measurements results. These instruments were previously characterized by the following experiments: stray light, photometric noise, resolution, photometric stability, baseline and linearity to determinate the accuracy and reproducibility of photometric and wavelength scale. 2 Reference Materials (Standards Identification) Six neutral density filters and three wavelength standards were used for the comparison of regular spectral transmittance measurements. The six neutral filters comprised: one set of three SRM neutral glass filters (S/N 119), with nominal transmittances of 1%, 3% and 50%, and one set of three SRM-2031 neutral filter (S/N 365) consisting of two chromium-coated fused silica plates with nominal transmittances of 10% and 30% and one clear fused-silica plate with a nominal transmittance of 90%, and one empty filter holder. The calibration certificate included with this SRM warns that, on account of theirs reflective nature, these metal-on-quartz filters can generate reflection effects in the sample compartment of the spectrophotometer witch may degrade the accuracy of transmittance measurements. The set of SRM-1930 neutral filters were to be calibrated for their regular transmittance factor over the spectral range 400 nm to 650 nm with a spectral bandpass of 1 nm. It was also requested to 1 These SRM's are available from the Standard Reference Materials Program and further information about them can be found at 2 Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the participants of this intercomparison or their respective National Laboratories, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. 3/26

4 report their regular transmittance factor at the following specified wavelengths and associated bandpass values (given in parentheses): 440 nm (2,2 nm), 465 nm (2,7 nm), nm (6,5 nm), 590 nm (5,4 nm) and 635 nm (6,0 nm). The three filters were identified as 1-119, and The set of SRM-2031 neutral filter (S/N 365) were to be calibrated for their regular spectral transmittance factor over the spectral range 220 nm to 650 nm with a spectral bandpass of 1 nm. The three filters were identified as , and The three wavelengths standards were calibrated for the wavelength of their transmittance minima over the wavelength range of 230 nm to 700 nm for the holmium oxide glass and solution filters, and over the range 400 nm 890 nm for the didymium oxide glass filters. All three wavelength standards were to be calibrated for spectral bandwidth (SBW) values of 1 nm, 2 nm, and 3 nm. 3 Description of the Instrumentation The spectrophotometers used in this intercomparison are characterized with estimates of systematic and statistical uncertainties. Their important features are given in Table 1. The features are the same for each measurement systems (models: Varian Cary 5E and Perkin-Elmer Lambda-19). The optical axis of the light beam that impinges the sample is normal to the filter; the image is in the central part of the filter. 3.1 General Characteristics of the instruments Table 1. General characteristics of the instruments: the Varian Cary 5E (used at and ) and the Perkin-Elmer Lambda-19 (used at and ). Band pass Lamp Grating Monochromator System Detection 1nm, 2 nm y 3 nm Tungsten and Deuterium Double grating Double monochromator Photomultiplier and Lead sulfide (PbS) 4 The combined standard uncertainty of the transmittance measurements is based on the combination in quadrature of the type B uncertainty in the transmittance scale, the type A standard uncertainty, given by the standard deviation of the independent sample measurements and the type B standard uncertainty in the wavelength scale. The combined standard uncertainty of the wavelength measurements is based on the combination in quadrature of the type B uncertainty in the wavelength scale as determined by the wavelength accuracy in measuring the position of known mercury and deuterium spectrum lines and the type A uncertainty due to the wavelength reproducibility of these measurements. The U reported in this paper are the expanded (k=2) uncertainties, representing a confidence level of 95%. It was obtained by assuming a normal distribution and by multiplying the combined standard uncertainty by a coverage factor k=2. The uncertainties of the other participants, U lab (Lab =, and ), are the combination in quadrature of the uncertainties indicated in certificate of calibration of references materials U cert. and the statistical uncertainty expressed as two times the standard deviation of the. 4/26

5 Wavelength U lab = [( 2 λ ) 2 + (U cert. ) 2 ] 1/2 Transmittance U lab = [( 2 T ) 2 + (U cert. ) 2 ] 1/2 DifferenceError = λ ι -λ total average ( All labs) Where: λ R = [ Σ(λ ι -λ ) 2 /n(n-1)] 1/2 DifferenceError = T ι -T total average ( All labs) Where: λ R = [ Σ(T ι -T ) 2 /n(n-1)] 1/2 Here T i and λ i are the measured transmittance and wavelength respectively, T and λ are the of the set of measurements and n is the number of measurements in the set. 5 Results Each laboratory reports the average of 10 measurements for each filter and its uncertainty with a 95% confidence level and k=2, according to the conditions previously described. For all measurements the air were taken as reference (100). The reference values for the comparison are calculated from the value of the participants results. The results for the wavelength scale are presented in the tables 2 to 10 and for the regular transmittance in the tables 11 to 16, also shown on graphics 1 to 9 and 10 to 15 respectively. Table 2a. Wavelength results and uncertainties for the calibration of holmium oxide glass for spectral bandwidth of 1 nm. λ λ λ λ Expended Expended Expended Expended 241,581 * 241, ,6 0,100 * 0,207 0,2 279, ,14 279, ,4 0,100 0,08 0,201 0,2 287, ,5 287, ,6 0,108 0,1 0,200 0,2 333, ,99 333, ,9 0,105 0,08 0,201 0,2 347, ,91 347,852 * 0,184 0,13 0,235 * 360, ,96 360, ,9 0,097 0,08 0,199 0,2 381, ,65 381,608 * 0,110 0,1 0,199 * 385, ,93 385,882 * 0,176 0,08 0,219 * 418, ,69 418,77 418,8 0,135 0,08 0,221 0,2 424, ,95 425,006 * 0,111 0,09 0,233 * 445, ,57 445,644 * 0,099 0,08 0,199 * 453, ,47 453, ,7 0,097 0,08 0,200 0,2 460, ,04 460,14 460,2 0,133 0,08 0,218 0,2 484, ,17 484,322 * 0,125 0,09 0,207 * 536, ,4 536, ,4 0,125 0,09 0,203 0,2 637, ,67 637, ,8 0,145 0,17 0,241 0,2 5/26

6 Table 2b. Reference value and difference to the reference value for holmium oxide glass for the spectral bandwidth of 1 nm. Wavelength 1 241,55-0,03 * 0,08-0, ,29-0,04 0,15-0,01-0, ,57-0,05 0,07 0,02-0, ,91 0,01-0,08 0,06 0, ,88 0,01-0,03 0,02 * 6 360,92-0,02-0,04 0,05 0, ,66-0,06 0,01 0,05 * 8 385,90 0,00-0,03 0,02 * 9 418,76-0,03 0,07-0,01-0, ,98 0,00 0,03-0,03 * ,64-0,06 0,07-0,01 * ,61-0,02 0,13-0,02-0, ,14-0,05 0,10 0,00-0, ,27-0,04 0,10-0,06 * ,42 0,03 0,02-0,04-0, ,67 0,09 0,00 0,05-0, Dispersion values for holmium oxide glass, SBW = 1 Difference to reference value Reference value wavelength Fig. 1 Wavelength results and uncertainties for the calibration of holmium oxide glass for spectral bandwidth of 1 nm. 6/26

7 Table 3a. Wavelength results and uncertainties for the calibration of holmium oxide glass for spectral bandwidth of 2 nm. λ λ λ λ Expended Expended Expended Expended 279, ,12 279,24 279,2 0,113 0,09 0,206 0,2 287, ,64 287, ,7 0,111 0,13 0,205 0,2 333, ,92 333, ,9 0,141 0,09 0,227 0,2 360, ,97 361, ,9 0,099 0,09 0,199 0,2 385, ,95 386,048 * 0,127 0,09 0,203 * 418, ,76 418,84 418,8 0,100 0,09 0,201 0,2 445, ,75 445,914 * 0,100 0,09 0,199 * 453, ,46 453, ,6 0,100 0,11 0,199 0,2 460, ,11 460, ,3 0,136 0,09 0,218 0,2 484, ,22 484,462 * 0,137 0,1 0,216 * 536, ,56 536, ,7 0,111 0,1 0,204 0,2 637, ,62 637, ,8 0,146 0,09 0,235 0,2 Table 3b. Reference value and difference to the reference value for holmium oxide glass for the spectral bandwidth of 2 nm. Wavelength 1 279,18 0,02 0,06-0,06-0, ,67-0,03 0,03 0,04-0, ,93-0,02 0,01-0,02 0, ,97-0,02 0,00-0,05 0, ,00 0,00 0,05-0,05 * 6 418,82-0,01 0,06-0,02-0, ,87-0,08 0,12-0,04 * 8 453,58-0,01 0,12-0,10-0, ,23-0,02 0,12-0,03-0, ,2-0,11 0,10 0,09 * ,63 0,03 0,07-0,08 0, ,68 0,08 0,06-0,01-0,12 7/26

8 0.35 Dispersion values for holmium oxide glass, SBW = 2 nm Reference value 0.25 Difference to reference value wavelength Fig. 2 Wavelength results and uncertainties for the calibration of holmium oxide glass for spectral bandwidth of 2 nm. Table 4a. Wavelength results and uncertainties for the calibration of holmium oxide glass for spectral bandwidth of 3 nm. λ λ λ λ Expended Expended Expended Expended 287, ,71 287,73 287,8 0,123 0,09 0,228 0,2 333, ,84 333, ,0 0,153 0,08 0,236 0,2 361, , ,1 0,100 0,08 0,201 0,2 418, ,74 418, ,8 0,116 0,08 0,204 0,2 446, ,99 446,222 * 0,097 0,08 0,199 * 453, ,34 453, ,7 0,104 0,08 0,199 0,2 460, ,2 460, ,5 0,136 0,08 0,218 0,2 484, ,45 484,86 * 0,158 0,11 0,235 * 536, ,65 536, ,9 0,118 0,09 0,207 0,2 637, ,5 637, ,7 0,138 0,09 0,249 0,2 8/26

9 Table 4b. Reference value and difference to the reference value for holmium oxide glass for the spectral bandwidth of 3 nm. Wavelength 1 287,74 0,07 0,03 0,01-0, ,91 0,06 0,07-0,08-0, ,10 0,04 0,10-0,10 0, ,85 0,03 0,11-0,15 0, ,14-0,06 0,15-0,08 * 6 453,59 0,01 0,25-0,15-0, ,40-0,01 0,20-0,09-0, ,74-0,17 0,29-0,12 * 9 536,79 0,02 0,14-0,08-0, ,59 0,17 0,09-0,19-0, Dispersion value for holmium oxide glass, SBW = 3 nm Reference value Difference to reference value wavelength Fig. 3 Wavelength results and uncertainties for the calibration of holmium oxide glass for spectral bandwidth of 3 nm. 9/26

10 Table 5a. Wavelength results and uncertainties for the calibration of holmium oxide solution for spectral bandwidth of 1 nm. λ λ λ λ 287, ,16 287,122 * 0,097 0,08 0,199 * 333, ,33 333,480 * 0,104 0,09 0,200 * 345, ,26 345,396 * 0,097 0,08 0,201 * 361, ,13 361,274 * 0,102 0,08 0,199 * 385, ,64 385,598 * 0,136 0,09 0,218 * 416, ,29 416,234 * 0,136 0,08 0,218 * 451, ,3 451,426 * 0,118 0,15 0,250 * 467, ,95 467,808 * 0,134 0,08 0,217 * 473, ,4 473,556 * 0,136 0,09 0,230 * 485, ,15 485,234 * 0,097 0,08 0,199 * 536, ,56 536,546 * 0,104 0,08 0,199 * 640, ,52 640,506 * 0,097 0,08 0,199 * Table 5b. Reference value and difference to the reference value for holmium oxide solution for the spectral bandwidth of 1 nm. Wavelength 1 287,16-0,04 0,00 0,04 * 2 333,44-0,07 0,11-0,07 * 3 345,37-0,09 0,11-0,09 * 4 361,25-0,10 0,12-0,10 * 5 385,65-0,06 0,01 0,05 * 6 416,29-0,07 0,00-0,11 * 7 451,40-0,07 0,10-0,12 * 8 467,88 0,00-0,07-0,13 * 9 473,51-0,05 0,11-0,05 * ,22-0,05 0,07-0,15 * ,58-0,05 0,02-0,16 * ,52-0,01 0,00-0,17 * 10/26

11 Difference to reference value Dispersion values for holmium oxide solution, SBW = 1 Reference value wavelength Fig. 4 Wavelength results and uncertainties for the calibration of holmium oxide solution for spectral bandwidth of 1 nm. Table 6a. Wavelength results and uncertainties for the calibration of holmium oxide solution for spectral bandwidth of 2 nm. λ λ λ λ 287, ,21 287,240 * 0,104 0,08 0,199 * 333, ,33 333,547 * 0,131 0,08 0,219 * 345, ,3 345,463 * 0,125 0,09 0,217 * 361, ,09 361,200 * 0,119 0,08 0,202 * 385, ,79 385,843 * 0,097 0,08 0,203 * 416, ,51 416,643 * 0,104 0,08 0,200 * 451, ,2 451,317 * 0,097 0,08 0,199 * 467, ,97 467,97 * 0,137 0,08 0,200 * 473, ,36 473,533 * 0,104 0,09 0,208 * 485, ,13 485,310 * 0,097 0,08 0,199 * 536, ,84 536,907 * 0,097 0,08 0,199 * 640, ,75 640,763 * 0,097 0,08 0,201 * 11/26

12 Table 6b. Reference value and difference to the reference value for holmium oxide solution for the spectral bandwidth of 2 nm. Wavelength 1 287,25-0,04 0,04 0,01 * 2 333,47-0,06 0,14-0,08 * 3 345,40-0,03 0,09-0,07 * 4 361,16-0,04 0,07-0,04 * 5 385,86-0,08 0,07 0,01 * 6 416,61-0,07 0,10-0,03 * 7 451,28-0,05 0,08-0,03 * 8 467,96 0,01-0,01-0,00 * 9 473,47-0,04 0,11-0,06 * ,26-0,08 0,13-0,05 * ,89-0,04 0,05-0,01 * ,79-0,07 0,04 0,03 * Difference to reference value Dispersion values for holmium oxide solution, SBW = 2 nm Reference value wavelength Fig. 5 Wavelength results and uncertainties for the calibration of holmium oxide solution for spectral bandwidth of 2 nm. 12/26

13 Table 7a. Wavelength results and uncertainties for the calibration of holmium oxide solution for spectral bandwidth of 3 nm. λ λ λ λ 286, ,05 287,027 * 0,105 0,08 0,199 * 333, ,29 333,540 * 0,167 0,08 0,219 * 345, ,41 345,707 * 0,105 0,08 0,209 * 361, ,09 361,283 * 0,105 0,08 0,201 * 386, ,95 386,107 * 0,105 0,08 0,213 * 417, ,81 417,033 * 0,097 0,08 0,199 * 451, ,18 451,437 * 0,097 0,08 0,201 * 473, ,47 473,730 * 0,119 0,08 0,206 * 485, ,09 485,360 * 0,104 0,08 0,202 * 537, ,15 537,317 * 0,104 0,08 0,199 * 641, ,09 641,203 * 0,097 0,08 0,211 * Table 7b. Reference value and difference to the reference value for holmium oxide solution for the spectral bandwidth of 3 nm. Wavelength 1 287,01 0,06-0,04-0,02 * 2 333,42 0,00 0,13-0,12 * 3 345,56 0,00 0,15-0,15 * 4 361,20-0,02 0,11-0,08 * 5 386,03 0,00 0,08-0,08 * 6 416,95-0,05 0,14-0,09 * 7 451,34-0,06 0,16-0,10 * 8 473,60 0,00 0,13-0,13 * 9 485,25-0,06 0,16-0,11 * ,25-0,04 0,10-0,07 * ,19-0,08 0,10-0,02 * 13/26

14 Difference to reference value Dispersion values for holmium oxide solution, SBW = 3 nm Reference value wavelength Fig. 6 Wavelength results and uncertainties for the calibration of holmium oxide solution for spectral bandwidth of 3 nm. Table 8a. Wavelength results and uncertainties for the calibration of didymium oxide glass for spectral bandwidth of 1 nm. λ λ λ λ 431, ,28 431, ,4 0,106 0,08 0,223 0,2 440, ,5 440, ,7 0,146 0,08 0,209 0,2 472, ,71 472, ,8 0,151 0,1 0,238 0,2 481, ,09 481, ,3 0,132 0,08 0,217 0,2 513, ,57 513, ,7 0,107 0,08 0,260 0,2 529, ,2 529, ,4 0,101 0,08 0,210 0,2 573, ,13 573, ,2 0,120 0,16 0,276 0,2 684, ,85 684, ,8 0,177 0,12 0,272 0,2 739, ,39 740, ,7 0,608 0,18 0,390 0,2 807, ,74 807, ,2 0,142 0,13 0,232 0,2 879, ,78 880,756 * 0,597 0,16 0,497 * 14/26

15 Table 8b. Reference value and difference to the reference value for didymium oxide glass for the spectral bandwidth of 1 nm. Wavelength 1 431,36-0,03 0,08-0,02-0, ,59-0,02 0,09 0,03-0, ,78-0,05 0,07-0,03 0, ,26-0,07 0,17-0,05-0, ,65-0,01 0,08-0,02-0, ,29 0,00 0,09-0,01-0, ,16 0,09 0,03-0,07-0, ,79 0,09-0,06-0,02-0, ,12 0,15-0,27-0,31 0, ,25-0,22-0,49-0,34 1, ,68 0,17 0,90-1,07 * Difference to reference value Dispersion values for didymium filter, SBW = 1 nm wavelength Fig. 7 Wavelength results and uncertainties for the calibration of didymium oxide glass for spectral bandwidth of 1 nm. 15/26

16 Table 9a. Wavelength results and uncertainties for the calibration of Didymium oxide glass for spectral bandwidth of 2 nm. λ λ λ λ 431, ,64 431, ,8 0,145 0,09 0,163 0,2 440, ,59 440, ,8 0,155 0,11 0,142 0,2 472, ,61 472, ,7 0,151 0,07 0,179 0,2 480, ,93 481, ,0 0,162 0,07 0,151 0,2 513, ,65 513, ,8 0,190 0,08 0,209 0,2 529, ,29 529, ,5 0,106 0,07 0,143 0,2 573, ,42 573, ,5 0,103 0,07 0,212 0,2 684, ,84 684, ,9 0,241 0,08 0,225 0,2 740, ,4 740, ,2 0,153 0,16 0,329 0,2 807, ,76 807, ,0 0,101 0,09 0,172 0,2 879, ,02 880,604 * 0,548 0,39 0,463 * Table 9b. Reference value and difference to the reference value for didymium oxide glass for the spectral bandwidth of 2 nm. Wavelength 1 431,77-0,03 0,13-0,03-0, ,71-0,04 0,12-0,02-0, ,67 0,03 0,06-0,03-0, ,03 0,04 0,10-0,13-0, ,73 0,02 0,08-0,04-0, ,40 0,04 0,11-0,09-0, ,46 0,01 0,04-0,05 0, ,83 0,10-0,01-0,06-0, ,26 0,10-0,14 0,02 0, ,25-0,25-0,51-0,46 1, ,78 0,07 0,76-0,83 * 16/26

17 Difference to reference value Dispersion values of didymium filter, SBW = 2 nm wavelength Fig. 8 Wavelength results and uncertainties for the calibration of didymium oxide glass for spectral bandwidth of 2 nm. Table 10a. Wavelength results and uncertainties for the calibration of Didymium oxide glass for spectral bandwidth of 3 nm. λ λ λ λ 440, ,69 440, ,1 0,132 0,08 0,237 0,2 472, ,45 472, ,6 0,153 0,08 0,256 0,2 480, ,65 480, ,0 0,107 0,08 0,225 0,2 513, ,77 514, ,0 0,190 0,08 0,253 0,2 529, ,43 529, ,8 0,122 0,08 0,229 0,2 573, ,69 573, ,1 0,115 0,08 0,281 0,2 684, ,82 685, ,0 0,263 0,08 0,284 0,2 740, ,46 740, ,4 0,169 0,15 0,271 0,2 807, ,81 807, ,2 0,118 0,08 0,243 0,2 879, ,82 880,832 * 0,428 0,19 0,465 * Table 10b. Reference value and difference to the reference value for didymium oxide glass for the spectral bandwidth of 3 nm. Wavelength 1 440,87 0,06 0,18-0,05-0, ,58 0,16 0,13-0,24-0, ,82 0,18 0,17-0,17-0, ,88 0,12 0,11-0,14-0, ,61 0,12 0,18-0,14-0, ,95-0,04 0,26-0,04-0, ,91 0,09 0,10-0,14-0, ,46 0,11 0,00-0,13 0, ,35-0,16-0,46-0,52 1, ,83-0,01 1,01-1,00 * 17/26

18 Difference to reference value Dispersion values of didymium filter, SBW = 3 nm wavelength Fig. 9 Wavelength results and uncertainties for the calibration of didymium oxide glass for spectral bandwidth of 3 nm. Table 11. Results for regular transmittance calibration and its uncertainty for filter a) Results Wavelength 250 9,9513 9,95 10, ,00 0,1003 0,18 0,1168 0, ,6313 9,68 9,9269 9,71 0,0904 0,09 0,1077 0, ,3028 9,37 9,5141 9,34 0,0901 0,08 0,1073 0, ,4703 9,55 9,6813 0,0900 0,07 0, ,5332 9,58 9,7389 9,58 0,0900 0,04 0,1077 0, ,2597 9,29 9,441 9,28 0,0900 0,04 0,1075 0, ,5503 9,6 9,7373 9,57 0,0900 0,05 0,1070 0, , ,48 10, ,43 0,1000 0,05 0,1157 0, , ,54 11, ,52 0,1100 0,08 0,1244 0, , ,58 12,7578 0,1200 0,12 0, /26

19 b) Reference value and difference to the reference value for the filter Wavelength Reference value Difference Difference Difference Difference ,0382 0,0868 0,088-0,2146 0, ,7364 0,1051 0,056-0,1905 0, ,3817 0,0789 0,012-0,1324 0, ,5672 0,0969 0,017-0,1141 * 400 9,6081 0,0749 0,028-0,1308 0, ,3172 0,0575 0,027-0,1238 0, ,6155 0,0652 0,015-0,1218 0, ,4936 0,0612 0,014-0,1416 0, ,5712 0,0690 0,031-0,1530 0, ,6276 0,0827 0,048-0,1302 * Tranmittance () Dispersion values of filter wavelength Fig. 10 Results for regular transmittance calibration and its uncertainty for filter Table 12: Results for regular transmittance calibration and its uncertainty for filter a) Results Wavelength , ,66 29,911 29,57 0,2625 0,33 0,2722 0, , ,69 29, ,63 0,2627 0,13 0,2787 0, , ,62 28, ,60 0,2501 0,1 0,2612 0, , ,51 28,719 0,2501 0,12 0, , ,2 28, ,22 0,2501 0,07 0,2610 0, , ,71 27, ,69 0,2401 0,07 0,2514 0, , ,95 28,127 27,89 0,2501 0,09 0,2600 0, , ,93 29, ,83 0,2501 0,1 0,2607 0, , ,15 30, ,07 0,2700 0,07 0,2807 0, , ,48 31,5784 0,2801 0,09 0, /26

20 b) Reference value and difference to the reference value for the filter Wavelength Reference value Difference Difference Difference Difference ,6702 0,1277 0,010-0,2408 0, ,6859 0,1601-0,004-0,2165 0, ,6768 0,0642 0,057-0,1930 0, ,5714 0,0862 0,061-0,1476 * ,2397 0,0805 0,040-0,1387 0, ,7427 0,0491 0,033-0,1361 0, ,9800 0,0285 0,030-0,1470 0, ,9299 0,0402 0,000-0,1439 0, ,1611 0,0331 0,011-0,1365 0, ,4913 0,0758 0,011-0,0871 * Dispersión values of filters Transmittance wavelength Fig. 11 Results for regular transmittance calibration and its uncertainty for filter Table 13. Results for regular transmittance calibration and its uncertainty for filter a) Results Wavelength , ,4 91, ,31 0,3918 0,69 0,3997 0, , ,91 92,112 91,97 0,3947 0,4 0,3914 0, , ,55 92, ,55 0,3813 0,5 0,3899 0, , ,71 92,7488 0,3807 0,22 0, , ,92 92, ,87 0,3804 0,31 0,3879 0, , ,94 93, ,73 0,3804 0,32 0,3896 0, , ,00 93, ,99 0,3804 0,44 0,3878 0, , ,10 93, ,70 0,3806 0,38 0,3893 0, , ,21 93,12 92,82 0,3804 0,18 0,3907 0, , ,15 93,132 0,3804 0,18 0,3876 * 20/26

21 b) Reference value and difference to the reference value for the filter Wavelength Reference value Difference Difference Difference Difference ,4568 0,0438 0,057-0,2448 0, ,9516 0,1338 0,042-0,1604-0, ,5682 0,0761 0,018-0,1080 0, ,7109 0,0370 0,001-0,0379 * ,8581 0,0872-0,062-0,0101-0, ,9037-0,0359-0,036-0,0987 0, ,0178-0,0241 0,018-0,0190 0, ,9915-0,0695-0,108-0,1109 0, ,0790-0,0866-0,131-0,0410 0, ,1517-0,0215 0,002 0,0197 * Dispersion values of filter Transmittance () wavelength Fig. 12 Results for regular transmittance calibration and its uncertainty for filter Table 14. Results for regular transmittance calibration and its uncertainty for filter a) Results Wavelength 440 0,5609 0,556 0,5541 0,56 0,0077 0,008 0,0584 0, ,7875 0,783 0,7802 0,79 0,0107 0,01 0,0589 0, ,7155 0,718 0,7084 0,72 0,0097 0,005 0,0588 0, ,6637 0,67 0,6541 0,66 0,0090 0,005 0,0586 0, ,8876 0,891 0,8785 0,89 0,0120 0,01 0,0592 0,04 21/26

22 b) Reference value and difference to the reference value for the filter Wavelength Reference value Difference Difference Difference Difference 440 0,5574-0,0035 0,001 0,0033-0, ,7849-0,0026 0,002 0,0047-0, ,7143-0,0011-0,004 0,0059-0, ,6630-0,0007-0,007 0,0089-0, ,8860-0,0015-0,005 0,0075-0, Dispersion values of filter Transmittance () wavelngth Fig. 13 Results for regular transmittance calibration and its uncertainty for filter Table 15. Results for regular transmittance calibration and its uncertainty for filter a) Results Wavelength 440 2,2959 2,275 2,2925 2,28 0,0289 0,02 0,0646 0, ,0219 3,006 3,0218 3,02 0,0376 0,013 0,0691 0, ,8434 2,851 2,8445 2,84 0,0355 0,023 0,0678 0, ,6338 2,648 2,6341 2,64 0,0331 0,013 0,0672 0, ,2863 3,297 3,2806 3,29 0,0410 0,018 0,0710 0,06 b) Reference value and difference to the reference value for the filter Wavelength Reference value Difference Difference Difference Difference 440 2,2869-0,0090 0,012-0,0056 0, ,0183-0,0036 0,012-0,0035-0, ,8449 0,0015-0,006 0,0004 0, ,6378 0,0039-0,010 0,0037 0, ,2893 0,0030-0,008 0,0087-0, /26

23 3.40 Dispersion values of filter 3.20 Transmittance () Wavelength Fig. 14 Results for regular transmittance calibration and its uncertainty for filter Table 16. Results for regular transmittance calibration and its uncertainty for filter a) Results Wavelength , ,78 49, ,55 0,2399 0,34 0,2481 0, , ,17 53, ,24 0,2563 0,27 0,2633 0, , ,7 52,605 52,43 0,2617 0,27 0,2690 0, , ,97 49, ,76 0,2396 0,26 0,2479 0, , ,07 48, ,82 0,2357 0,22 0,2429 0,24 b) Reference value and difference to the reference value for the filter Wavelength Reference value Difference Difference Difference Difference ,7743-0,1118-0,006-0,1049 0, ,2233-0,0291 0,053-0,0115-0, ,5885-0,0311-0,112-0,0165 0, ,8523-0,0011-0,118 0,0265 0, ,9300 0,0018-0,140 0,0318 0, /26

24 54.00 Dispersion values of filter Tranmittance () wavelngth Fig. 15 Results for regular transmittance calibration and its uncertainty for filter Discussion and conclusions Each participant uses its own standard procedure for the measurement of wavelength and transmittance, also estimated uncertainty is according the normal procedure implanted by each laboratory. Then the results represent the actual ability of the four labs to measure wavelength and spectral transmittance as shown in the previous tables and graphs. 6.1 Conclusions 1 Data shown are with a confidence interval of 95%. From the obtained results, the dependence of these data was judged statistically insignificant, so that the average differences were taken to be representative of wavelength and transmittance accuracy of the spectrophotometers and the comparability of the services provided by the participating labs. 7 Acknowledgements The measurements were made by Guillermo Valencia Luna 1, Mario Noel 2, Iakyra Bougleux 3 and Yvonne Barnes 4, The project was managed by Arquímedes Ruiz 1 and Joanne Zwinkels 2 who also provided valuable advice assistance in preparing this report. 1 The symbol (*) on the tables indicate that some values of were not included because the following reason : The transmittance values by was not evaluated, at the wavelength 360 nm and 635 nm at neutral density filter Were not gave the wavelength values at 807 and 879, with SBW= 1,2 and 3 Were not gave the values of holmium oxide solution Were not gave the wavelength values at 333, 381,385 and 484 with SBW= 1 Were not gave the wavelength values at 347, 385, 445, 473 and 484 with SBW= 2 Were not gave the wavelength values at 385, 445, 484 with SBW= 3 24/26

25 8 References 1. ASTM E "Standard Practice for the Periodic Calibration of Narrow Band-Pass Spectrophotometers", Annual Book of ASTM Standards 2000, Vol , p (2000). 2. ASTM E "Standard Practice for Describing and Measuring Performance of Ultraviolet, Visible, and Near-Infrared Spectrophotometers", Annual Book of ASTM Standards 2000, Vol , p (2000). 3. J.G. Vinter, revised by P. Knee, "Wavelength Calibration", Chapter 7 in Standards and Best Practice in Absorption Spectrometry, C. Burgess and T. Frost, eds., Blackwell Science Ltd., Oxford UK, C.N. Dodd and T.W. West, "Spectral Transmittance Properties of Rare-Earth Glasses", J. Opt. Soc. Am. 51, (1961). 5. J.M. Vandenbelt, "Holmium Filter for Checking the Wavelength Scale of Recording Spectrophotometers", J. Opt. Soc. Am. 51, (1961). 6. H.J. Keegan, J.C. Schleter, and V.R. Weidner, "Ultraviolet Wavelength Standard for Spectrophotometry", J. Opt. Soc. Am. 51, 1470 (1961). 7. J. McNeirney and W. Slavin, "A Wavelength Standard for Ultraviolet-Visible-Near Infrared Spectrophotometry", Appl. Optics 1, (1962). 8. A.G. Reule, "Errors in Spectrophotometry and Calibration Procedures to Avoid Them", J. Res. NBS 80A, (1976). 9. V.R. Weidner, R. Mavrodineanu, K.D. Mielenz, R.A. Velapoldi, K.L. Eckerle, and B. Adams, "Spectral Transmittance Characteristics of Holmium Oxide in Perchloric Acid", J. Res. NBS 90, (1985). 10. Mavrodineanu, R. et al. Glass Filters filters as a standard Reference Material for Spectrophotometry Selection, preparation, certification, and Use of SRM 930 and SRM 1930, Spec. Publ , Mavrodineanu, R. And Baldwin, J.R. Metal-on-Quartz Filters as a Standard Reference Material for Spectrofotmetry SRM 2031, NBS Spec. Pub , Mavrodineanu, R. An Accurate Spectrophotometer for Measuring the Transmittance of solid and Liquid Materials, J. Res. Nat. Bur. Stand., 1972, 76A, 5, /26

26 13. V.R. Weidner, R. Mavrodineanu, K.D. Mielenz, R.A. Velapoldi, K.L. Eckerle, and B. Adams, Holmium Oxide Solution Wavelength Standard from 240 to 640 nm SRM 2034, NBS Special Publication (1986). 14. C.J. Sansonetti, M.L. Salit, and J. Reader, "Wavelengths of Spectral Lines in Mercury Pencil Lamps", Appl. Optics 35, (1996). 15. Reference Material DMR 41e, Centro Nacional de Metrología, Querétaro, Mexico 16. Standard Reference Material SRM 2034, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA 17. ASTM E "Standard Practice for Measuring Practical Spectral Bandwidth of Ultraviolet- Visible Spectrophotometers", Annual Book of ASTM Standards 2000, Vol , p. 877 (2000). 18. C. Zhu and L.M. Hanssen, "Studies of a Polystyrene Wavenumber Standard for Infrared Spectrometry", 11 th International Conference of Fourier Transform Spectrometry, AIP Proceedings 430, ed. J.A. de Haseth, , American Institute of Physics, New York (1998). 19. Guide to the Expression of in Measurement, ISBN , 1 st Ed. ISO, Geneva, Switzerland (1993) 20. B.N. Taylor and C.E. Kuyatt, "Guidelines for Evaluating and Expressing the of Measurement Results," Technical Note 1297, U.S. Government Printing Office, Washington DC (1994). General Information 1) This report may not be reproduced except with written consent from the Optical and Radiometric Division (). 2) This report is intended for internal use only. Received: May 7, 2000 and revised: May 18, 2000, by 1. Optical and Radiometric Division (), 2 Photometry and Radiometry (), 3. Optical Metrology Division () 4. Optical Technology Division (). 26/26